The principle is usual and well-known of operating labeling machines with an uninterrupted flow of containers incoming at a container inlet of these machines in order to achieve a continuously running labeling process. This continuous labeling process is achieved, in part, by providing controllable buffer and storage stretches arranged in the transport direction upstream of the labeling machine, and by controlling the operating speed or capacity of the labeling machine. Due to the buffer and storage stretches, gaps in the flow of containers conducted to the labeling machine can be avoided in the event of a further container handling machine upstream of the labeling machine causing such gaps, due, for example, to malfunction.
In this situation, it is important for changes in the operating speed of the labeling machine to take place in such a way that all the components involved in this machine, and in particular also the labeling unit, can follow the changes and the operating speed respectively of the labeling machine without mechanical failure of these components and/or without tearing, fluttering, knocking, extension etc. occurring of a label strip being used. Particular attention must be paid to such components at changes of the operating speed of the labeling machines, which exhibit a high mechanical and/or dynamic moment of inertia, such as label strip rolls from which the processed label strip is drawn off.
The principle is further known of configuring labeling machines in such a way that they themselves react to gaps in the incoming flow of containers, for example, by sensors provided at the container inlet, and, in the event of a container being missing at a labeling position, that they stop the preparation and/or handover of the label.
It is also usual for labeling units for the processing of label strips to be equipped with label strips with label strip stores or short “strip stores,” which in the short term provide the possibility of compensating for surplus or missing label material. The setting of a dancer roller, which comprises at least one strip deflection, then controls drives of the labeling unit to draw off the label strip from the label strip store or label strip roll and to provide the labels at the labeling position.
Particular problems arise, however, if it is intended that a labeling machine should be used in a container handling system in block form together with a further container handling machine, such as a stretch blow-molding machine, for producing the containers by stretch blow-molding, i.e. together with a container handling machine that does not allow for continuous regulation of its capacity, but that does allow for a stepped change in this capacity.
“Block form,” in this context, means that the containers are transported in an exact cycle from the further container-handling machine, such as a stretch blow-molding machine, via a transport stretch to the container inlet of the labeling machine, i.e. in a container flow in which the containers exhibit a division spacing interval between one another, which is specifically determined by the cycle of the further container handling machine and by container retainers of the container-transport stretch.
Such a container handling system in block form does indeed have the advantage that the containers can be held securely, for example suspended from a flange or neck ring formed beneath the container aperture, and transported securely to the labeling machine, and, due to the absence of buffer and storage stretches, in which the containers are arranged, for example, standing upright with their container bases on transport belts, the structural volume of the system can be reduced, and gaps due to containers falling over are avoided.
Nevertheless, in particular at high capacity outputs, as defined by the number of containers prepared and labeled per time unit, gaps in the container flow cause substantial problems. This is attributable in particular to the fact that, for example at capacities of 60,000 to 70,000 containers per hour, gaps occurring in the container flow cannot be reacted to with conventional labeling machines and their control systems, and in particular due to the fact that the time available is not sufficient for a necessary change in the operational mode of the labeling machine (stopping and starting of this machine at the beginning and end of a gap), as well as the necessary reduction or running up again of the speed of components of the labeling unit.